(1) Field of the Invention
The present invention relates to the manufacture of books and particularly to the mating of covers with moving book blocks. More specificially, this invention is directed to a cover application device for book binding machines and especially to apparatus for feeding book covers into registration with continuously moving book blocks. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
(2) Description of the Prior Art
In the binding of books, book blocks having a glued spine are customarily moved along a conveying mechanism and it is necessary to provide means for feeding the book covers, which are individually withdrawn from a magazine, into registration with the blocks. An example of a prior art book cover transport and alignment mechanism may be seen from U.S. Pat. No. 4,080,678. In the apparatus of U.S. Pat. No. 4,080,678 the means which engage the book covers are driven by a chain system which operates at periodically alternating speeds. Thus a cover being transported is first caused to move at a speed which is higher than that of the continuously moving book blocks until it catches up with the book block. Subsequently, through cooperation with the tongs which are supporting the moving book block, the cover will be brought into alignment and synchronised movement with the block as a result of a braking action. Apparatus of the type disclosed in U.S. Pat. No. 4,080,678 has the disadvantage that, when the cover transporting means catches up with the book block conveyor and suddenly decelerates, the friction between the cover and the engaging means of its transport system is often insufficient to keep the cover aligned with the engaging means. When misalignment occurs, because of slipping of the cover, the cover will not be precisely aligned with the book block.
As a further disadvantage of prior cover application devices, the constant change in speed and direction of the chains of the transport system imposes forces on the system which cause noisy operation, the need for constant readjustment and lead to premature wear.